A5060536345- Quasicrystal Structures and Properties
- Rare-earth and actinide compounds
- Iron-based superconductors research
- Magnetic Properties of Alloys
- X-ray Diffraction in Crystallography
- High-pressure geophysics and materials
- Theoretical and Computational Physics
- Mineralogy and Gemology Studies
- Crystal Structures and Properties
- Analytic and geometric function theory
- Inorganic Chemistry and Materials
- Magnetic Properties and Applications
- Pigment Synthesis and Properties
- Microstructure and mechanical properties
- Physics of Superconductivity and Magnetism
- Magnetic Properties and Synthesis of Ferrites
- Superconductivity in MgB2 and Alloys
- Fullerene Chemistry and Applications
- Magnetic properties of thin films
- Organic and Molecular Conductors Research
- Non-Destructive Testing Techniques
- Health Systems, Economic Evaluations, Quality of Life
- Electromagnetic Scattering and Analysis
- Advanced Mathematical Theories and Applications
- Nanocluster Synthesis and Applications
Tokyo University of Science
2019-2025
Aoyama Gakuin University
2023-2024
The University of Tokyo
2006-2023
Toyama Prefectural University
2023
University of Toyama
2007-2023
Kavli Institute for the Physics and Mathematics of the Universe
2014
Sony Computer Science Laboratories
2006
Kanto Chemical (Japan)
1981-1984
Denka (Japan)
1981-1984
This paper presents a simple algorithm and compact sensor for localization of magnetic dipole. First, we derive an explicit formula, where the dipole position, irrespective its posture, is directly reconstructed from field spatial gradient tensor. Then, develop unit consisting three orthogonal loop coils, planar gradiometers, coaxial measuring field, nondiagonal, diagonal components tensor, respectively. Localization experiments are conducted, maximum error about 7 mm when source-sensor...
Quasicrystals (QCs), first discovered in 1984, generally do not exhibit long-range magnetic order. Here, we report on order the real icosahedral quasicrystals (i QCs) Au–Ga–Gd and Au–Ga–Tb. The Au65Ga20Gd15 i QC exhibits a ferromagnetic transition at TC = 23 K, manifested as sharp anomaly both susceptibility specific heat measurements, along with an appearance of Bragg peak below TC. This is observation quasicrystal, contrast to spin-glass-like behaviors observed for other found date....
We discovered a ferromagnetic Au-Ga-Dy icosahedral quasicrystal (i QC), not only with high phase purity but also tunable composition. The isothermal magnetization of the polycrystalline i QC was closely investigated and mean-field-like nature transition is elucidated. Moreover, maximum Weiss temperature (θ_{p}) QCs found at electrons-per-atom (e/a) ratio 1.70 being well consistent those ACs, validating tunability magnetic properties on basis θ_{p}-e/a scheme for first time. Thus, present...
Abstract Van der Waals layered transition-metal chalcogenides are drawing significant attention owing to their intriguing physical properties. This group of materials consists abundant members with various elements, having a variety different structures. However, they all crystalline materials, and the properties van quasicrystals have never been studied date. Here, we report on discovery superconductivity in quasicrystal Ta 1.6 Te. The electrical resistivity, magnetic susceptibility,...
Magnetism of Tsai-type 1/1 approximants has been extensively investigated for the last decade. The experimental results on are reviewed and magnetic behaviors classified discussed in terms average electron-per-atom (e/a) ratio. paramagnetic Curie-Weiss temperature Θp is found to oscillate a universal manner as function e/a ratio, order systematically changes with variation Θp. In addition, recent work shows that 2/1 also follow trend observed approximants, which implies phase diagram can be...
This study reports the successful synthesis and comprehensive characterization of Ti3RhSiO Ti3IrSiO, earliest identified members Ti-based Au4Al-type materials. These compounds crystallize in cubic space group P213 (No. 198), with refined lattice parameters 6.75362(2) Å 6.75524(1) Å, respectively. Oxygen plays a crucial role stabilizing phase, as confirmed by synchrotron X-ray diffraction absence this phase oxygen-free samples. First-principles calculations resistivity measurements reveal...
We discover the experimental case of a quantum valence criticality leading to breakdown Fermi liquid state.
We report the observation of antiferromagnetic (AFM) transitions in 1/1 and 2/1 quasicrystal approximants having slightly different electron-per-atom $(e/a)$ ratios, same Au-Ga-Eu system, at N\'eel temperatures 7.0 8.5 K, respectively. This clearly demonstrates that an order survives when degree approximation to quasicrystals is raised provided $e/a$ ratio kept nearly same. Since, unlike approximant, approximant has all building blocks necessary for construction quasicrystal, this finding...
The existence of various magnetic orders has recently been established in the Tsai-type 1/1 approximant Au-Al-Gd by variation electron-per-atom (e/a) ratio [Ishikawa et al. Phys. Rev. B 98, 220403(R) (2018)]. Here, we report ferromagnetic (FM) 2/1 quasicrystal approximants and show that order higher-order can be tailored starting from known approximants. (Au,Cu)-(Al,In)-$R\phantom{\rule{4pt}{0ex}}(R=\mathrm{Gd},\mathrm{Tb})2$/1 are synthesized simultaneous substitution isovalent elements Cu...
Understanding the strange metallic behavior that develops at brink of localization in quantum materials requires probing underlying electronic charge dynamics. Using synchrotron radiation–based Mössbauer spectroscopy, we studied fluctuations metal phase β-YbAlB 4 as a function temperature and pressure. We found usual single absorption peak Fermi-liquid regime splits into two peaks upon entering critical regime. interpret this spectrum nuclear transition, modulated by nearby valence whose...
A magnetic phase diagram of the non-Heisenberg Tsai-type 1/1 Au-Ga-Tb approximant crystal (AC) has been established across a wide electron-per-atom (e/a) range via magnetization and powder neutron diffraction measurements. The revealed exotic ferromagnetic (FM) antiferromagnetic (AFM) orders that originate from unique local spin icosahedron common to icosahedral quasicrystals (iQCs) ACs; noncoplanar whirling AFM order is stabilized as ground state at e/a 1.72 or less whereas FM was found...
Iron based metal pigments exhibiting coercivity as high 1000-1400 Oe, and iron nitride (Fe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> N) 500- 800 Oe for magnetic recording media was prepared from acicular particles of iron-cobalt oxalate, oxides or oxyhydrates by reduction in hydrogen following nitridation ammonia. The the pigment maintained characteristic original shape oxalates, oxyhydrates. In addition, contained a number pores...
A three dimensional geometrically frustrated Mott insulator of tetrahedral cluster compound GaTa4Se8 has been studied by X-ray diffraction, susceptibility and specific heat measurements. Temperature dependence the magnetic shows an anomaly peak at 53 K, which is supposed to be structural transition from cubic tetragonal structure on analogy GaNb4S8. Moreover, small g factor compared with GaNb4S8 revealed strong spin orbit coupling (SOC) inherent in this 5d compound.
The Fe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> N pigments were prepared by nitridation of the in an ahnosphere ammonia-hydrogen. pigments, precursors, reduction hydrogen iron oxyhydrates having various particle sizes. realtionship between coercivity and specific surface area pigment was clarified. relationship magnetic properties those also chemical stabilities investigated. From results electron diffraction patterns, it is clear...
We report an angle-resolved photoemission (ARPES) study of $\ensuremath{\beta}\ensuremath{-}{\mathrm{YbAlB}}_{4}$, which is known to harbor unconventional quantum criticality (QC) without any tuning. directly observe a quasiparticle peak (QP) emerging from hybridization, characterized by binding energy and onset coherence both at about 4 meV. This value conforms with previously observed reduced Kondo scale 40 K. Consistency earlier carriers in...
Recent discovery of various magnetism in Tsai-type quasicrystalline approximants, whose alloys rare-earth ions located on icosahedral apices are coupled with each other via the Ruderman--Kittel--Kasuya--Yosida interaction, opens an avenue to find novel originating from symmetry. Here we investigate classical and quantum magnetic states cluster within Heisenberg interactions all bonds. Simulated annealing numerical diagonalization performed obtain ground states. We qualitative correspondence...
Audio or video recording performances of various magnetic tapes including Co-modified γ-Fe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , metal and Fe xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> N having their coercivity range 600-700 Oe were investigated. The prepared by the conventional method using above pigments which to give 600-800 Oe. electromagnetic characteristics...
This study reports the first observation of ferromagnetic (FM) order in non-Au-based approximant crystals (ACs) using a novel approach whereby total electron-per-atom (e/a) ratio spin-glass Ga50Pd36Gd14 1/1 AC is lowered by simultaneously substituting certain ratios tri-valent Ga and zero-valent Pd mono-valent Au. The emergence FM this method was confirmed via magnetic susceptibility, magnetization, specific heat measurements. findings open up vast opportunities developing long-range orders...
van der Waals (vdW) layered transition-metal chalcogenides are attracting significant attention owing to their fascinating physical properties. This group of materials consists abundant members with various elements, having a variety different structures. However, all vdW studied date have been limited crystalline materials, and the properties quasicrystals not yet reported. Here, we report on discovery superconductivity in quasicrystal Ta1.6Te. The electrical resistivity, magnetic...
Given the parallelism between physical properties of Ce- and Yb-based magnets heavy fermions due to electron-hole symmetry, it has been rather odd that transition temperature compounds is normally very small, as low ∼1K or even lower, whereas Ce counterparts may often have well exceeding 10 K. Here, we report our experimental discovery reaching 20 K in a compound at ambient pressure. The Mn substitution Al site an intermediate valence state α−YbAlB4 not only induces antiferromagnetic record...
α-YbAlB4 shows strong valence fluctuation as well heavy fermion behavior at low temperatures. It has been theoretically suggested that the quantum criticality owing to found in Yb ions plays an important role peculiar properties of this material. In work, we measured X-ray absorption spectra (XAS) and magnetic circular dichroism (XMCD) L3 edge high fields up 40 T. is XAS are almost independent field 2 K, which proves there no significant change range. The XMCD spectrum exhibits a distinct...
The structural properties of β-YbAlB4 with an orthorhombic Cmmm symmetry have been investigated by powder X-ray diffraction analysis using synchrotron radiation under high pressure (up to ∼20 GPa) at 7 K. Although the refined lattice parameters exhibit no discontinuity and dependence volume was well reproduced Murnaghan's equation state up GPa, detailed analyses observed patterns reveal local structure changes in B layers 3.5(2) 5.8(1) GPa. strongly affect bonding structures among conduction...